Recovery and separation of W and Mo from high-molybdenum synthetic scheelite in HCl solutions containing H2O2

• Leaching of high molybdenum synthetic scheelite in HCl–H2O2 solution is studied.
• W and Mo are effectively extracted at room temperature and low acidity.
• The difference of W and Mo in thermal stability of peroxyacid is verified.
• W is separated from Mo based on difference of thermal stability of peroxyacid.
• Tungsten can be selectively recovered as H2WO4 by thermal decomposition.

In this research, W and Mo were separated and recovered from high-molybdenum synthetic scheelite by leaching with HCl solutions containing H2O2 as the chelating agent. The effects of the leaching parameters, such as temperature, leaching time, HCl concentration and H2O2 concentration, on the recovery of W and Mo were investigated. The results show that W and Mo were effectively extracted at room temperature and low acidity. With a leaching temperature of 30 °C, an L:S ratio of 10:1, an HCl concentration of 1.5 mol/L, an H2O2 concentration of 2.5 mol/L and a leaching time of 40 min, the recovery of W and Mo was 97.7% and 99.4%, respectively. Thermal decomposition was then employed to treat the leaching solution. W was transformed into tungstic acid, whereas Mo remained in solution. At 60 °C, 97.47% of W was precipitated, and the separation factor reached 105.